• International Journal of Naval Architecture and Ocean Engineering
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• v.7 no.3
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• pp.478-489
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• 2015

In the present study, a hydrodynamic hull-form optimization algorithm for a container ship was presented in terms of the minimum wave-making resistance. Bell-shaped modification functions were developed to modify the original hull-form and a sequential quadratic programming algorithm was used as an optimizer. The wave-making resistance as an objective function was obtained by the Rankine source panel method in which non-linear free surface conditions and the trim and sinkage of the ship were fully taken into account. Numerical computation was performed to investigate the validity and effectiveness of the proposed hull-form modification algorithm for the container carrier. The computational results were validated by comparing them with the experimental data.

• Journal of the Society of Naval Architects of Korea
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• v.43 no.5 s.149
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• pp.550-559
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• 2006

A design procedure for a ship with minimum total resistance was developed using a numerical optimization method called SQP(Sequential Quadratic Programming) and a CFD technique based on the Rankine source panel method with the nonlinear free surface boundary conditions. During the whole optimization process the geometry of the hull shape was represented based on the NURBS(Non-uniform rational B-spline) technique and the modification of the hull shape was controlled using the Bell-shaped distribution function to keep the fairness of the hull shape before and after the hull modification. The numerical analysis was carried out using 4000TEU container ship in the towing tank facility installed in the Pusan national university to know the validity of the developed algorithm for this study. As the results of the numerical analysis it proved that the resistance of the optimized hull is conspicuously reduced in comparison with the original hull in a wave-making resistance point of view.

• Journal of Information Display
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• v.3 no.2
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• pp.13-18
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• 2002

Numerical simulation is one of the most useful tools to study gas discharge phenomena that occur in alternating current plasma display panel (AC-PDP) cell. Most PDP cell simulations have been performed for two-dimensional cell, is cross-section along the address electrode. We developed a three-dimensional PDP simulator and applied it to a T-shaped electrode cell in order to show the effects of sustain electrode shape that cannot be included in two-dimensional simulation. The dependence of power consumption on electrode shape and area in the simulation showed the same trend as experiment.

• Proceedings of the KIEE Conference
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• 2000.07c
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• pp.1818-1820
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• 2000

Due to recent technology advances, needs for flat panel displays, plasma display panels(PDPs) whose advantages are simple structure, high resolution, wide viewing angle is increasingly expected to be the first flat panel of large screen, walt hanging TVs. But the luminance and luminous efficiency of color PDP is net up to the level of a CRT. So, New electrode shape which is different from the conventional electrode has to propose to improve the luminance and luminous efficiency. In this paper, we suggested new shaped electrodes. In new shaped electrode, the discharge current was reduced compared with conventional type by reducing the unnecessary diffusion loss near the barrier rib. However, the luminance was nearly the same as conventional type. So, the luminous efficiency improved about 35%.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.33 no.7
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• pp.700-705
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• 2009

In order to enhance the dynamic stiffness of automotive panel, effect of bead and curved surface was investigated. Modal test was performed for principle specimens which have various kinds of beads, holes and curved surfaces. Test was also performed for conventional dash panel assembly and rear floor panel assembly and curved shaped ones. Results showed that curved shape increased the natural frequency of automotive panel more effectively than the bead. Finite element analysis was also performed and yielded good match with the test results.

• Journal of the Korean Society for Precision Engineering
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• v.14 no.9
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• pp.101-107
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• 1997

A sectional analysis of auto-body panel stamping is carried out by using the rigid-plastic FEM based on the membrane theory. The auto-body panel material is assumed to possess normal anisotropy and to obey Hill's new yield criterion and its associated flow rule. A method of contact treatment is proposed in which the skew boundary condition for arbitarily shaped tools is successively used during iteration. Deformation of each section of trunk-lid panel is simulated and composed to get the three-dimensional shape by using CAD technique. It was shown that the composition of the two-dimensional section analysis gives almost the same results as the full three-dimensional analysis.

• Composites Research
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• v.23 no.2
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• pp.31-39
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• 2010

In this paper, composite panels with hat-shaped stiffeners were made using the co-curing, co-bonding and secondary bonding methods. Co-curing is a manufacturing method in which the hat part and the plate are cured simultaneously in a manner that is more cost effective than other methods. Co-bonding is a method in which the stacked prepregs are cured with other cured parts, and secondary bonding is a method in which cured parts are bonded together using an adhesive. A rubber mold was manufactured for co-curing of composite panel with hat-shaped stiffeners, and finite element analyses were done to evaluate the expanding pressure of the rubber mold consistent with the curing temperature. The manufactured panels were also evaluated using a 3-D measurement tester and an ultrasonic tester. Pull-off tests were performed to evaluate their mechanical properties.

• Steel and Composite Structures
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• v.18 no.5
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• pp.1177-1195
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• 2015

Six specimens are tested to investigate the cyclic behavior of beam-to-column abnormal joints in steel moment-resisting frames, which are designed according to the principle of strong-member and weak-panel zone. Key parameters include the axial compression ratio of column and the section depth ratio of beams. Experimental results indicate that four types of failure patterns occurred during the loading process. The $P-{\Delta}$ hysteretic loops are stable and plentiful, but have different changing tendency at the positive and negative direction in the later of loading process due to mechanical behaviors of specimens. The ultimate strength tends to increase with the decrease of the section depth ratio of beams, but it is not apparent relationship to the axial compression ratio of column, which is less than 0.5. The top panel zone has good deformation capacity and the shear rotation can reach to 0.04 rad. The top panel zone and the bottom panel zone don't work as a whole. Based on the experimental results, the equation for shear strength of the abnormal joint panel zone is established by considering the restriction of the bottom panel zone to the top panel zone, which is suitable for the abnormal joint of H-shaped or box column and beams with different depths.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.26 no.6_spc
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• pp.667-673
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• 2016

Canister with composite sandwich panel has been suggested owing to its higher stiffness and strength over a weight for square shaped canisters. The pyro shock induced by a short time explosion inside a canister is generally considered to be the most severe source of load affecting on the entire structure. Therefore, in this study, the approach and modeling method to identify the effect of pyro shock on canister with composite sandwich panel in a numerical way were mainly discussed. Moreover, the verification was implemented through comparison with test results.

• Laser Solutions
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• v.16 no.4
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• pp.1-6
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• 2013

Femtosecond laser patterning of ITO on a touch screen panel with a shaped fs laser beam was investigated. A quasi flat-top beam was formed using a variable mask and a planoconvex lens. The spatial profile of the original Gaussian beam and the shaped beam were monitored by a CCD beam profiler. The laser patterned ITO film was examined using an optical microscope, Scanning Electron Microscope (SEM) with Energy Dispersive X-ray Spectroscopy (EDS), and Atomic Force Microscope (AFM). It turned out that the quality of the ITO pattern fabricated by a shaped beam is superior to that of the pattern without beam shaping in terms of debris generation, height of the craters, and homogeneity of the bottom. Optimum processing window was determined at the laser irradiance exhibiting 100% removal of Sn. The removal rate of In was measured to be 83%.